Looking for a manga
I'm looking for a yuri one-shot manga i read about a year ago - I don't remember many details, but i thought i'd give looking for it a shot.
It was either a one-shot or a short story, but i'm pretty sure it was in a short one-shot anthology.
The story was of two girls who were in an S relationship, and i believe a teacher was dissaproving of it. Through the manga we find out the reason the teacher was dissaproving of it was because her own S relationship fizzled out after her girlfriend graduated.
The main thing i rememeber about this manga was that the teachers romance involved her meeting her girlfriend underneath/behind a piano in the music room of the school, and at the end of the manga, the teacher finds out that her feelings weren't actually unrequited and that her at the time girlfriend had carved her response under the piano unbenownst to the teacher until now.
Sorry if this is the wrong place to ask, or has been tagged wrong, but any help would be appreciated!